Childhood and adolescent cancer is a significant health issue globally, with varying survival rates across countries. While advancements in cancer treatment have improved survival rates, the impact of cancer on the affected child's family, particularly siblings, remains poorly understood. Siblings often experience disruptions in family dynamics, attention disparities, and increased responsibilities due to their brother or sister's illness. Psychological consequences, such as anxiety and depression, have been reported in siblings, yet psychological support for them is limited. The long-term effects of cancer on siblings and their adjustment to non-normative events require further investigation. This study aimed to explore the needs of siblings of young people with cancer in the Quebec context. Thematic analysis of qualitative interviews revealed six primary needs of siblings of young people with cancer: attention and acknowledgment, emotional support, medical knowledge and preparatory information, inclusion, nurturing family relationships, and instrumental support. Addressing these needs through improved family functioning and tailored interventions can better support siblings throughout and after the cancer experience. The findings of this study contribute to the existing literature and provide insights for healthcare professionals, educators, and parents to offer appropriate support to siblings of young people with cancer during the cancer journey.